High resolution images of Betelgeuse are available on the ESO website showing before and after images of the surface taken with the Sphere instrument .Could it be dust that is causing the dimming. hears the link https://www.eso.org/public/news/eso2003/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+EsoTopNews+%28ESO+Top+News%29
Peter